Get a summary of the completed state of only certain sub-items

Hello,

We have a board where every item has many sub-items, and those sub-items have a column which is the timeframe in which the sub-item is to be completed (immediately, after two weeks, etc.)

I’d like to add a column to the item which shows either how many “immediate” sub-items are complete (number or percentage).

Is this possible in some way? If not via a column, then is it possible with a different view or some sort of report?

Thanks in advance for any help.